Adaptive balloon weaning algorithm with automated REBOA facilitates proximal homeostasis during reperfusion in a swine hemorrhagic shock model

Abstract

Objective

Restoration of distal blood flow is critical to successfully salvage patients with resuscitative endovascular balloon occlusion of the aorta (REBOA). Yet, ideal methods for REBOA deflation to restore flow and simultaneously avoid proximal hypotension remain undefined. Adaptive balloon titration algorithms to guide deflation may prevent large hemodynamic fluctuations during weaning. We hypothesize that automated REBOA weaning can both augment proximal hemodynamics and avoid hypotension during attempts to completely deflate the REBOA in a swine model of hemorrhagic shock.

Methods

Fifteen swine underwent 30% controlled hemorrhage followed by 30 minutes of zone 1 REBOA to recreate a class III hemorrhage. Next, the REBOA was deflated with an automated syringe running an adaptive algorithm that prioritized proximal mean arterial blood pressure (pMAP) >62.5 mmHg during transfusion of shed blood. Upon post-hoc analysis, animal pMAP responses (hypertensive [HTN] vs normotensive [NORM]) and the discovery of low-volume distal flow (low volume in the HTN group and minimal volume in the NORM group) during the intended complete REBOA phase created two distinct cohorts. The performance of the adaptive weaning algorithm during attempts to completely deflate the REBOA was compared between the groups.

Results

The two cohorts (HTN, n = 5 [low volume distally] and NORM, n = 10 [minimal volume distally]) differed in pMAP (P = .001) and distal flow (P = .001) during REBOA. During the wean phase, cohorts were similar in pMAP, time with carotid flow within 90% of baseline, and time above the pMAP threshold of 62.5 mmHg (P = .20, P = .59, and P = .95, respectively) despite the weaning algorithm permitting 14.5 mL/kg more distal aortic flow for the HTN cohort (P = .001).

Conclusion

Automated REBOA weaning is feasible and maintains consistent hemodynamics across various physiologic profiles. Automated endovascular devices that can interpret and adapt to a range of hemodynamic physiology will soon facilitate precision resuscitation for patients requiring endovascular aortic occlusion. These findings highlight the need for adaptive control to overcome variability in hemodynamics and differences in resuscitation intensity across clinical contexts.